Electromagnetic steel plate forming member, electromagnetic steel plate laminator, permanent magnet type synchronous rotating electric machine rotor provided with the same, permanent magnet type synchronous rotating electric machine, and vehicle, elevator, fluid machine, and processing machine using the rotating electric machine

ABSTRACT

An electromagnetic steel plate forming member provides the two magnet holes for inserting therein the two permanent magnets per pole along the V-shape, which are provided in the region of the radial pole pitch lines OP provided in the rotor core at the predetermined pole pitch angle θ, one magnet hole is displaced in a direction apart from the center line OC of the pole pitch lines OP, and the other magnet hole is displaced in a direction approaching to the center line OC of the pole pitch lines OP.

The present invention claims priority from Japanese Patent ApplicationNo. 2007-072140 filed on Mar. 20, 2007, the entire content of which isincorporated herein by reference.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to an electromagnetic steel plate formingmember, an electromagnetic steel plate laminator, a permanent magnettype synchronous rotating electric machine rotor provided with thislaminator, a permanent magnet type synchronous rotating electricmachine, and a vehicle, an elevator, a fluid machine, and a processingmachine using the rotating electric machine. These are used as a drivemotor or a generator for a vehicle such as a hybrid car, a fuel cell caror an electric car; or as a drive motor or a generator for an industrialpower saving machine such as a crane, a winding machine, an elevator, anelevator in a multi-level parking zone, a compressor or a blower forwind or water power, a fluid machine such as a pump, or a processingmachine including mainly a semiconductor manufacturing member or amachine tool.

2. Description of the Related Art

Recently, from viewpoints of prevention of global warming and resourceconservation, duties to be performed by a vehicle such as a hybrid car,and an industrial power saving machine are becoming very important. Inorder to perform the duties, it is necessary to reduce CO₂-discharge,and improve the amount of energy consumption and efficiency.

For such the vehicle such as the hybrid car or the industrial powersaving machine, a permanent magnet type synchronous rotating electricmachine is required, which has characteristics that high output andhigh-speed rotation are possible, reliability is high and efficiency isgood, rotation speed is variable, and controllability is good. As arotating electric machine satisfying this condition, there is asynchronous motor in which a permanent magnet is included in a rotor,that is, an interior permanent magnet (IPM) motor. Since this motorproviding size reduction and weight reduction are realized, the range ofits use in the field of the industrial power saving machine isincreasing. For example, the motor is applied also to a crane, a windingmachine, an elevator, an elevator of a multi-level parking zone, acompressor or a blower for wind or water power, a fluid machine such asa pump, and a processing machine including mainly a semiconductormanufacturing member or a machine tool. In the present invention, IPMmotor will be mainly described

FIG. 6 is a front view of an electromagnetic steel plate forming memberblanked to mold a rotor core in a first related art.

In FIG. 6, an electromagnetic steel plate forming member 35 is composedof a thin disc-shaped electromagnetic steel plate for forming a rotorcore. In this electromagnetic steel plate forming member 35, a magnetichole 31 for inserting therein a permanent magnet is provided per polewhen the rotor is formed. An outer bridge 32 is formed between thismagnet hole 31 and a circumferential surface of the rotor. When theplural electromagnetic steel plate forming member 35 are laminated inthe block shape, an electromagnetic steel plate laminator (rotor core 34in FIG. 7) is manufactured (refer to, for example, JP-A-2006-211826,Specification P. 4, and FIGS. 1 to 3 and Toyo Denki Technical Report No.111, 2005-3, P. 13 to P. 21).

Next, the operational principle of the interior permanent magnet motorwill be described.

FIG. 7 is a front sectional view of a main part of an interior permanentmagnet motor to which the rotor in the first related art is applied. Inthe shown motor, the number of magnetic poles of permanent magnets ofthe rotor is six poles, and the number of magnetic poles of salientpoles of a stator (the same number as the number of slots) is 36 pieces.

In FIG. 7, regarding the operation of the motor, in the rotor 30 inwhich a permanent magnet 33 is inserted into the interior of a rotorcore 34, the gap flux density becomes high in a q-axis constituting amagnetic convex portion which is small in magnetic resistance, and thegap flux density becomes low in a d-axis constituting a magnetic concaveportion which is large in magnetic resistance. By such the saliency ofthe rotor 30, the following relation is produced: Lq>Ld, when Lq isq-axis inductance and Ld is d-axis inductance. Therefore, reluctancetorque produced by change in flux density in addition to magnet torquemay be used, so that more increase in efficiency may be expected. Themagnet torque generates by a magnetic attraction force and a magneticrepulsion force between a magnetic field by the permanent magnet 33 ofthe rotor 30 and a rotating magnetic field by a stator winding housed(not-shown) in a slot 42 in a stator core 41 of the stator 40. Thereluctance torque generates by attraction of the salient pole portion ofthe rotor 30 to the rotating magnetic field by the stator winding (notshown).

Next, a second related art will be described with reference to FIG. 8.

FIG. 8 is a front view of an electromagnetic steel plate forming memberblanked to mold a rotor core in the second related art (refer to, forexample,

-   JP-A-2005-039963, Specification P. 4 to P. 6, and FIGS. 1 and 2,-   JP-A-2005-057958, Specification P. 4 to P. 7, and FIGS. 1 and 5,-   JP-A-2005-130604, Specification P. 8, and FIG. 1,-   JP-A-2005-160133, Specification P. 8, and FIG. 1,-   JP-A-2002-112513, Specification P. 5, and FIGS. 1 and 3, and-   JP-A-2006-254629, Specification P. 7 and P. 8, and FIG. 4.)

In FIG. 8, an electromagnetic steel plate forming member 50 is composedof a thin disc-shaped electromagnetic steel plate for forming a rotorcore. In this electromagnetic steel plate forming member 50, two magnetholes 52 and 53 are provided in the V-shape so that two magnets per poleare inserted on the rotor outer diameter side symmetrically with respectto radial pole pitch lines provided at a predetermined pole pitch angle,when a rotor is formed. An outer bridge 54 is formed between the outerend portion of the magnet holes 52, 53 and a circumferential surface ofthe rotor. Further, in the electromagnetic steel plate forming member50, a center bridge 51 is provided between the magnet holes 52 and 53.When the plural electromagnetic steel plate forming member 50 arelaminated in the block shape, an electromagnetic steel plate laminator(rotor core 57 in FIG. 9) is manufactured.

Next, the operation will be described with reference to FIG. 9.

FIG. 9 is a front sectional view of a main part of an IPM motor to whichthe rotor in the second related art is applied, which showsschematically a positional relation of poles between a stator and arotor which generate optimum rotating torque. FIGS. 10A and 10B arediagrams for explaining of the operation of the IPM motor in the secondrelated art. FIG. 10A is a schematic diagram showing the operation whenthe motor rotates normally, and FIG. 10B is a diagram showing a relationbetween a current phase which generates a rotating magnetic field of themotor and torques. The number of magnetic poles of permanent magnets ofthe rotor in the shown motor is eight poles, and the number of magneticpoles of salient poles of a stator (the same number as the number ofslots) is 48 pieces.

In FIGS. 9 and 10A, the IPM motor has a permanent magnet type rotor 50in which permanent magnets 55, 56 having the same size as the size ofmagnet holes 52, 53 are inserted into the magnet holes. In such theconstitution, a magnetic field by the permanent magnets 55, 56 embeddedin the interior of a rotor core 57 and a rotating magnetic field by astator winding housed (not-shown) in a slot 62 in a stator core 61 of astator 60 attract and repel each other, thereby to generate a magnettorque. Further, since the magnetic resistance in the direction of aq-axis orthogonal to the direction of a d-axis which is a magnet axisbecomes smaller than that in the d-axis direction, saliency structure isprovided. Therefore, a q-axis inductance Lq becomes larger than a d-axisinductance Ld, and reluctance torque generates by this saliency. InFIGS. 9 and 10A, the permanent magnets 55, 56 which are embedded in themagnet holes 52, 53 and arranged in the V-shape are isosceles.Therefore, a repulsion-boundary point of magnetic fluxes by thepermanent magnets in an outer iron core portion sandwiched between thetwo permanent magnets having the same size which are opposed to eachother in the same poles is located in the center of the outer iron coreportion of the rotor 50, and on a center line OC passing through acenter of the radial pole pitch lines OP.

In FIGS. 9 and 10A, though a force for giving rotary energy to the rotor50 is actually composed by strength of current flowing in the statorwinding (not shown) in the slot 62 and the like, its description issimplified here. Flux density distribution of the motor will bedescribed, paying attention to a pole located at 12 o'clock.

The d-axis repulsion-boundary point of the outer iron core portionsurrounded by the two permanent magnets 55, 56 of the same polarity islocated in the center of the surface of the rotor 50. In case that thepoles formed by the stator windings (not shown) in the slots 62 areshown as in FIGS. 9 and 10A, on the gap surface between the stator 60and the rotor 50, the left side with respect to the repulsion-boundarypoint on the line OC becomes an attraction part constructed so that thestator is the N-pole and the rotor is the S-pole, and the right sidewith respect to the repulsion-boundary point on the line OC becomes arepulsion part constructed so that both of the stator and the rotorbecome the S-pole. On the surface of the rotor 50, the attraction partbecomes dense in magnetic flux and the repulsion part becomes sparse inmagnetic flux. Therefore, magnet torque which is about to move the rotor50 from the side in which the magnetic flux is dense to the side inwhich the magnetic flux is sparse, that is, in the clockwise directionacts on the rotor 50. Further, the q-axis flux flows mainly in teeth 63of the stator 60 opposed to the salient poles.

In the description related to FIG. 10A, since attraction is producedbetween the magnetic fields by the permanent magnets 55, 56 of the rotor50 and the rotating magnetic fields by the stator windings (not shown)in the slots 62 and the d-axis salient pole portion of the rotor 50 isattracted to the rotating magnetic field by the stator winding (notshown), the flux density in the oblique line portion becomesparticularly high. At this time, with respect to the S-pole component ofthe permanent magnets and the S-pole component by the stator windings(not shown), the N-pole component by the windings is short. Therefore,the reluctance torque which is about to move the rotor 50 in a directionwhere the magnetic flux of the S-pole component is shortened, that is,in the clockwise direction acts on the rotor 50.

Here, as shown in FIG. 10B, the magnet torque which is produced by themagnetic attraction force and the magnetic repulsion force between themagnetic field by the magnet and the rotating magnetic field by thewinding shows a relation of a curve in the figure, and the reluctancetorque generated by the attraction of the salient pole portion of therotor to the rotating magnetic field by the winding shows a relation ofa curve in the figure. Hereby, by putting the magnet torque and thereluctance torque together, a torque shown by a thick solid line in thefigure may be generated.

However, in the second related art, in the outer iron core portionformed between the upper surface of the two permanent magnet insertionholes and the outer diameter of the rotor core, the q-axis flux byarmature reaction is easy to be saturated. Therefore, the reluctancetorque may not be utilized, so that it is difficult to obtain largetorque in the starting time or in abrupt change in load.

Further, as shown in the second related art, in the shape in which thetwo permanent magnets are arranged in the V-shape per pole, magneticanisotropy is stronger than that in the shape having flat arrangement ofthe permanent magnets as shown in the first related art. However, theanisotropy is not sufficiently used, and this shape in the secondrelated art does not attribute to improvement of motor efficiency in thelow-speed operation time and in the light-load operation time.

SUMMARY OF INVENTION

With referring to the above problems, one or more embodiments of theinvention provide an electromagnetic steel plate forming member, anelectromagnetic steel plate laminator, a permanent magnet typesynchronous rotating electric machine rotor provided with the same, apermanent magnet type synchronous rotating electric machine, and avehicle, an elevator, a fluid machine, and a processing machine usingthe rotating electric machine, which saturation of q-axis flux may besuppressed in an outer iron core portion formed between upper surfacesof two magnet holes arranged in V-shape and an outer diameter of a rotorthereby to realize utilization of reluctance torque and improvement ofmagnet torque, and a large torque may be obtained in the starting timeor in the starting abrupt change of load thereby to obtain goodefficiency.

According to a first aspect of the invention, a thin disc-shapedelectromagnetic steel plate forming member for forming a rotor coreincluding permanent magnets therein, wherein first and second magnetholes for inserting therein two magnets per pole are formed, in a rangeof radial pole pitch lines provided for the thin disc-shapedelectromagnetic steel plate forming member at a predetermined pole pitchangle, along a v-shape having a rotation center side as a vertex, thefirst and second magnet holes are partitioned by a center bridge locatedat a vertex portion of the V-shape, and one of the first and the secondmagnet holes is displaced in a direction apart from a center line ofpole pitch lines, and the other is displaced in a direction approachingto the center line of the pole pitch lines.

According to a second aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein the first and thesecond magnet holes have an asymmetrical shape.

According to a third aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein a length in a radiusdirection of one of the first and the second magnet holes is longer thana length in the radius direction of the other.

According to a fourth aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein the first and thesecond magnet holes are positioned so that a distance of an iron coreportion from an outer end surface of each hole to a circumferentialsurface of the thin disc-shaped electromagnetic steel plate formingmember is substantially the same.

According to a fifth aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein arcuate spaces forpreventing flux leakage are provided, for both end portions in a radiusdirection of each of the first and the second magnet holes, in a bulgingshape toward an outer circumferential side.

According to a sixth aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein arcuate spaces forpreventing flux leakage are provided, for both end portions in a radiusdirection of each of the first and the second magnet holes, in a bulgingshape toward an inner circumferential side.

According to a seventh aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein each of the firstand the second magnet holes includes an arcuate space for preventingflux leakage which bulges outward at a larger curvature than a curvatureof a corner portion of the magnet hole so as to include a cornerportion.

According to an eighth aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein the first and thesecond magnet holes have a substantial rectangular.

According to a ninth aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein the first and thesecond magnet holes have an arcuate.

According to a tenth aspect of the invention, the thin disc-shapedelectromagnetic steel plate forming member, wherein a cavity portion isprovided in an area of the thin disc-shaped electromagnetic steel plateforming member which is determined by stress limit by centrifugal forceand is located on the radial pole pitch line.

According to an eleventh aspect of the invention, an electromagneticsteel sheet laminator constituted in a block shape by laminating theplural thin disc-shaped electromagnetic steel plate forming member.

According to a twelfth aspect of the invention, A permanent magnet typesynchronous rotating electric machine rotor provides a rotor coreconstituted by the thin disc-shaped electromagnetic steel sheetlaminator, and a first and a second permanent magnets which are insertedinto a first magnet hole and a second magnet hole inside the rotor coreto generate fields.

According to a thirteenth aspect of the invention, the permanent magnettype synchronous rotating electric machine rotor, wherein in an ironcore portion formed between the outer end surfaces of the first and thesecond magnetic holes and a circumferential surface of the rotor core,magnetic fluxes formed by the first and the second permanent magnets aredistributed with displacement in the circumferential direction from acenter of radial pole pitch lines provided in the rotor core at apredetermined pole pitch angle.

According to a fourteenth aspect of the invention, the permanent magnettype synchronous rotating electric machine rotor, wherein the rotor is arotor of an 8-pole interior permanent magnet rotating electric machine.

According to a fifteenth aspect of the invention, a permanent magnettype synchronous rotating electric machine provides, and a statorarranged around the rotor.

According to a sixteenth aspect of the invention, the permanent magnettype synchronous rotating electric machine, wherein the number P ofmagnetic poles of permanent magnets arranged in magnet holes of therotor and the number M of salient magnetic poles arranged in salientpoles of the stator satisfies P=2(n+1) (n is an integer which is one ormore) and M=6P.

According to a seventeenth aspect of the invention, the permanent magnettype synchronous rotating electric machine wherein the rotating electricmachine is an interior permanent magnet rotating electric machine inwhich the number of magnetic poles of the permanent magnets is 8 poles.

According to an eighteenth aspect of the invention, a vehicle providesthe permanent magnet type synchronous rotating electric machine used asa drive motor for driving wheels.

According to a nineteenth aspect of the invention, a vehicle providesthe permanent magnet type synchronous rotating electric machine used asa generator.

According to a twentieth aspect of the invention, an elevator providesthe permanent magnet type synchronous rotating electric machine used asa drive motor.

According to a twenty-first aspect of the invention, a fluid machineprovides the permanent magnet type synchronous rotating electric machineas a drive motor.

According to a twenty-second aspect of the invention, a processingmachine provides the permanent magnet type synchronous rotating electricmachine used as a drive motor.

According to the present invention, in the range of the radial polepitch lines provided in the rotor core at the predetermined pole pitchangle, one of the two magnet holes for inserting therein the twopermanent magnets per pole along the V-shape is displaced in thedirection apart from the center line of the pole pitch lines, and theother is displaced in the direction approaching to the center line ofthe pole pitch lines. Hereby, the magnetic fluxes formed by the twopermanent magnets are distributed with displacement in thecircumferential direction from the center of the pole pitch lines in therotor core. Therefore, in the iron core portion formed between the upperend surfaces of the two magnet holes arranged in the V-shape and theouter circumferential portion of the rotor core, saturation of theq-axis flux may be suppressed, and both utilization of the reluctancetorque and improvement of the magnet torque can be realized. As theresult, the permanent magnet type synchronous electric machine rotor andthe permanent magnet type synchronous electric machine can be realized,which may obtain large torque also in the starting time and in abruptchange of load, are good in efficiency, and are used in a field such asa vehicle, an elevator, a fluid machine, a processing machine and thelike.

Other aspects and advantages of the invention will be apparent from thefollowing description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an electromagnetic steel plate forming memberblanked in order to form a rotor core, which shows an embodiment of theinvention,

FIG. 2 is an enlarged front sectional view of a rotor to which theelectromagnetic steel plate forming member is applied, which shows astructure of the rotor,

FIG. 3 is a front sectional view of a main part of an IPM motor to whichthe rotor is applied, which represents schematically a positionalrelation of magnetic poles between a stator and the rotor which generatean optimum rotation torque,

FIG. 4A is a diagram for explaining the operation of the IPM motor,which is a schematic diagram showing the operation when the motorrotates normally,

FIG. 4B is a diagram for explaining the operation of the IPM motor,which is a diagram showing a relation between a current phase whichgenerates a rotating magnetic field of the motor and torque,

FIG. 5A is a diagram for explaining the operation of the IPM motor,which is a schematic diagram showing the operation when the motorrotates reversely,

FIG. 5B is a diagram for explaining the operation of the IPM motor,which is a diagram showing a relation between a current phase whichgenerates a rotating magnetic field of the motor and torque,

FIG. 6 is a front view of an electromagnetic steel plate forming memberblanked in order to mold a rotor core in a first related art,

FIG. 7 is a front sectional view of a part of an IPM motor to which therotor in the first related art is applied,

FIG. 8 is a front view of an electromagnetic steel plate forming memberblanked in order to mold a rotor core in a second related art,

FIG. 9 is a front sectional view of a part of an IPM motor to which therotor in the second related art is applied, which shows schematically apositional relation of poles between a stator and a rotor which generateoptimum rotating torque,

FIG. 10A is a diagram for explaining of the operation of the IPM motorin the second related art, which is a schematic diagram showing theoperation when the motor rotates normally, and

FIG. 10B is a diagram for explaining of the operation of the IPM motorin the second related art, which is a diagram showing a relation betweena current phase which generates a rotating magnetic field of the motorand torque.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

FIG. 1 is a front view of an electromagnetic steel plate forming memberblanked in order to form a rotor core, which shows an embodiment of theinvention, and FIG. 2 is an enlarged front sectional view of a rotor towhich the electromagnetic steel plate forming member is applied, whichshows a structure of the rotor.

In FIG. 1, reference numeral 1 is an electromagnetic steel plate formingmember, 2 and 3 are first and second magnet holes, and 4 is an outerbridge. Further, in FIG. 2, reference numeral 5 is a center bridge, 6and 7 are first and second permanent magnets, 8 is a cavity portion, 10is a rotor, 11 is a rotor core, and 20, 21, 22, 23, 24, and 25 arearcuate spaces for preventing flux leakage. Reference character O is acenter of rotation, OP is a pole pitch line, OC is a center line of thepole pitch lines, θ is a pole pitch angle, La and Lb are respectivelylengths in a radius direction of the first and second magnet holes 2 and3, and Cr is a distance of an iron core portion between the upper endsurface of the magnet hole 2, 3 and a circumferential surface of therotor core 11.

In FIG. 1, the electromagnetic steel plate forming member 1 is a thindisc-shaped electromagnetic steel plate for forming a rotor core. In aregion of radial pole pitch lines provided in this disc-shapedelectromagnetic steel plate forming member 1 at a predetermined polepitch angle, two magnet holes for inserting therein two magnets per poleare provided in the shape of V-shape having the rotation center side ofthe core as a vertex. The outer bridge 4 is located at a portion betweenthe outer end portion of the magnet hole 2, 3 of this electromagneticsteel plate forming member 1 and the outer circumferential portion ofthe rotor. Further, the center bridge 5 which partitions the magnetholes is provided in the electromagnetic steel plate forming member 1 soas to be located at the vertex portion of the V-shaped magnet holes 2,3. When the plural electromagnetic steel plate forming member 1 arelaminated in the block shape, an electromagnetic steel plate laminator(rotor core 11 in FIG. 1) is manufactured.

Next, in FIG. 2, characteristics of the first and second magnet holes 2,3 for inserting therein the two permanent magnets 6, 7 per pole in therotor core 11 formed of the electromagnetic steel plate forming member 1shown in FIG. 1 will be described in detail. In the region of the radialpole pitch lines OP provided along the V-shape having the rotationcenter side of the core 11 as a vertex at the predetermined pole pitchangle θ, the first magnet hole 2 is displaced in the direction apartfrom the center line OC passing through a center of the two pole pitchlines OP, and the second magnet hole 3 is displaced in the directionapproaching to the center line OC passing through a center of the twopole pitch lines OP.

These first and second magnet holes 2, 3 are arranged asymmetrically,and the length La in the radius direction of the first magnet hole 2 islonger than the length Lb in the radius direction of the second magnethole 3.

Further, the first and second magnet holes 2, 3 are provided in therotor core 11 in such positions that the distance Cr of the iron coreportion from the outer end surface of each hole for inserting thereinthe magnet 6, 7 to the outer circumferential portion of the rotor core11 is uniform.

Further, in the first and second magnet holes 2, 3, at both end portionsin the radius direction of the respective magnet holes, the arcuatespaces 20, 21, 22, and 23 for preventing flux leakage are provided inthe bulging shape toward the outer circumferential side or the innercircumferential side.

Further, the arcuate spaces 24 and 25 are provided shape which isbulging outward at a curvature larger than a curvature of the cornerportion so as to include a corner portion of each of in the first andsecond magnet holes 2, 3 respectively. The first and second magnet holes2, 3 described in this embodiment may be formed in the substantiallyrectangular shape or alternatively arcuate.

Further, the cavity portion 8 is provided in an area determined bystress limit by centrifugal force and located on the radial pole pitchline OP in the rotor core 11 formed of the electromagnetic steel plateforming member 1.

Next, an IPM motor to which the rotor according to the present inventionis applied will be described.

FIG. 3 is a front sectional view of a main part of an IPM motor to whichthe rotor according to the present invention is applied, whichrepresents schematically a positional relation of magnetic poles betweena stator and a rotor which generate an optimum rotation torque. Thenumber of magnetic poles of permanent magnets of the rotor in FIG. 3 iseight poles, and the number of magnetic poles of salient poles of thestator (it is equal to the number of slots) is 48 pieces. Combination ofthe magnet number and the slot number is the same as that in the secondrelated art.

In the IPM motor, permanent magnets 6, 7 embedded in a rotor 10 arearranged in the V-shape, and the same poles thereof face to each other.Though their thicknesses in the circumferential direction are the same,a length in the diameter direction of one permanent magnet 6 is longerthan the other permanent magnet 7. Further, distance Cr of an iron coreportion between the outer end surface of each permanent magnet and theouter circumferential portion of the rotor 10 is provided with the samedepth. Further, an open angle of the permanent magnets 6, 7 shown inFIG. 3 with respect to a rotation center of the rotor 10 is set to thesame angle as the open angle of the permanent magnets 55, 56 shown inFIG. 10 in the second related art. Accordingly, a repulsion-boundarypoint of magnetic fluxes by the permanent magnets in the outer iron coreportion sandwiched between the two permanent magnets 6 and 7 having thesame poles and the different length is located on the side of thepermanent magnet 7 which is short in length in the radius direction,that is, in a position δ-displacement in the circumferential directionfrom a center line Q-Q passing through a center of an opening angle(open angle) α of the permanent magnets 6, 7 arranged in the modifiedV-shape (on a center line OC of pole pitch lines of the rotor 10).

FIG. 3 shows the example in which the number of magnetic poles of thepermanent magnets arranged in the magnet holes of the rotor is 8 poles,and the number of salient magnetic poles arranged in salient poles(number of slots) of stator is 48 pieces. Preferably, this combinationis represented by the following relation.P=2(n+1) (n is an integer which is one or more), and M=6P,wherein P is the number of magnetic poles of the permanent magnets inthe rotor, and M is the number of magnetic poles of the salient poles ofthe stator.

By the combination thereof, a rotating electric machine which reducescogging and vibration, and operates at high output and with highefficiency may be obtained.

Next, an operation of normal rotation of rotating electric machine willbe described.

FIGS. 4A and 4B are diagrams for explaining the operation of the IPMmotor, which FIG. 4A is a schematic diagram showing the operation whenthe motor rotates normally, and FIG. 4B is a diagram showing a relationbetween a current phase which generates a rotating magnetic field of themotor and torque.

In FIG. 4A, a magnetic repulsion-boundary point of a d-axis in an outeriron core portion surrounded by the two same-pole permanent magnets 6, 7which are different from each other in length is on the surface of therotor 10 located on the outside of the bottom portion of theV-arrangement. In the following description, the amount of displacementon its surface is taken as a declination (δ) which is the amount ofdisplacement from the center line OC of the pole pitch lines OP by aboutone slot of the stator as shown in FIG. 3.

In case that poles formed by stator windings (not shown) attached in theslots 14 of the stator core 13 are as shown in FIG. 4A, on a gap surfacebetween the stator and the rotor, the left side of the magneticrepulsion-boundary point (existing on the line OC) becomes an attractiveportion in which the stator winding side is the N-pole and the permanentmagnet side is the S-pole, and the right side thereof becomes arepulsive portion in which both the stator winding side and thepermanent magnet side are the S-poles. Though the attractive portionbecomes dense in magnetic flux and the repulsive portion becomes sparsein magnetic flux, since the attractive portion is smaller in the numberof the N-poles on the stator side generated by the current direction ofthe stator windings is smaller than that in the related art exampleshown in FIG. 10, the attractive portion is higher in flux density thanthat in the example shown in FIG. 10. Further, since the repulsiveportion is larger in the number of the S-poles on the stator side thanthat in the example shown in FIG. 10, the repulsive portion is lower influx density than that in the example shown in FIG. 10. Since itsdifference of density is large, magnet torque which works on the rotorso as to move the rotor from the dense flux side to the sparse flux sidebecomes larger than that in the example shown in FIG. 10. Further, inFIG. 4A, though the open angle α of the two permanent magnets 6, 7 withrespect to the rotation center of the rotor is the same as that in theexample shown in FIG. 10, since the magnetic repulsion-boundary point inthe d-axis is displaced by about one slot (δ in FIGS. 3 and 4), thenumber of the magnetic poles of the salient poles (teeth) of the statoropposed to the salient pole of the rotor in which the q-axis flux flowsbecomes substantially two, while it is one in the example in FIG. 10.Therefore, magnetic saturation is difficult to occur. In the descriptionrelated to FIG. 3, since attraction occurs between the magnetic fieldsby the permanent magnets of the rotor and the rotating magnetic fieldsby the windings, and the d-axis salient pole portion of the rotor isattracted to the rotating magnetic fields by the windings, the fluxdensity in the portion shown by oblique lines in FIG. 4A becomesparticularly high. At this time, the N-pole component becomes furthershorter with respect to the S-pole component of the permanent magnetsand the S-pole component of the windings by one slot than that in theexample of FIG. 10, so that reluctance torque which is about to move therotor in the direction where the magnetic flux of the S-pole componentis shortened, that is, in the clockwise direction works more stronglythan that in the example of FIG. 10.

Next, a relation between current phase and torque of the permanentmagnet type synchronous rotating electric machine will be described.

As shown in FIG. 4A, in the iron core portion formed between the outerend surfaces of the first and second magnet holes 2, 3 and the outercircumferential portion of the rotor core 11, the magnetic fluxes formedby the first and second permanent magnets 6, 7 are distributed withdisplacement from the center line OC of the radial pole pitch lines OPprovided in the rotor core 11 at the predetermined pole pitch angle inthe circumferential direction of the rotor core 11. Accordingly, bydisplacing the d-axis flux, magnetic resistance of the d-axis becomeslarge, and the q-axis inductance Lq becomes increasingly larger than thed-axis inductance Ld. Therefore, since saliency becomes remarkable,reluctance torque is easy to generate. Simultaneously, in order tosuppress the q-axis flux saturation, the permanent magnet arrangement isdisplaced so that the number of the magnetic poles of the salient poles(teeth) of the stator opposed to the q-axis in the pole pitch lines OPis increased. Hereby, the saturation of the q-axis flux may bemitigated. FIG. 4B shows a curve in a relation of the magnet torquegenerated by the magnetic attraction and the magnetic repulsion betweenthe magnetic fields by the magnets and the rotating magnetic fields bythe windings, and the reluctance torque generated by the attraction ofthe salient pole portion of the rotor to the rotating magnetic field bythe winding. Therefore, an overall torque shown by a thick solid line inFIG. 4B may be generated by putting the magnet torque and the reluctancetorque together.

Next, an operation of reverse rotation of rotating electric machine willbe described.

FIGS. 5A and 5B are diagrams for explaining the operation of the IPMmotor, which FIG. 5A is a schematic diagram showing the operation whenthe motor rotates reversely, and FIG. 5B is a diagram showing a relationbetween a current phase which generates a rotating magnetic field of themotor and a torque.

FIG. 4 shows an optimum rotating torque position in case that therotating electric machine rotates clockwise (normally), while FIG. 5shows an optimum rotating torque position in case that the rotatingelectric machine rotates counterclockwise (reversely).

In FIG. 5A, the left side of the same-pole repulsion-boundary point ofthe d-axis of the rotor is a repulsive portion in which both the statorwinding side and the permanent magnet side are the S-poles. Further, theright side is an attractive portion in which the stator winding side isthe N-pole and the permanent magnets side is the S-pole. Herein,magnetic torque, which is about to move the rotor from the attractiveportion in which the flux density is dense to the repulsive portion inwhich the flux density is sparse, that is, in the counterclockwisedirection acts on the rotor. FIG. 5B shows the relation in this casebetween the current phase of the permanent magnet type synchronousrotating electric machine and the torque. Since overall torque isbasically the same as that in case of normal rotation of the rotatingelectric machine, it is omitted.

As shown in FIG. 3, of the two magnet holes 2, 3 for inserting thereinthe two permanent magnets 6, 7 per pole along the V-shape, which areprovided in the region of the radial pole pitch lines OP provided in therotor core 11 at the predetermined pole pitch angle θ, one magnet hole 2is displaced in a direction apart from the center line OC of the polepitch lines OP, and the other magnet hole 3 is displaced in a directionapproaching to the center line OC of the pole pitch lines OP. Hereby,since the magnetic fluxes formed by the two permanent magnets 6,7 aredistributed with displacement from the center line OC of the pole pitchlines OP in the rotor core 11 in the circumferential direction, both themagnet torque and the reluctance torque in the V-arrangement of thepermanent magnets of which lengths in the radius direction are differentimprove with respect to the one-rotating direction, and efficiency ofthe permanent magnet type synchronous rotating electric machine may beincreased, compared with the rotor in which the permanent magnetsembedded in the rotor are arranged in isosceles V-shape as described inthe second related art shown in FIG. 10. The improvement of the magnettorque with respect to the one-rotating direction may improve greatlyefficiency of the permanent magnet type synchronous rotating electricmachine in a low-speed at light load area where the current is low.

Further, generally, centrifugal force acts on the embedded permanentmagnet by the rotation of the rotor 10, so that the permanent magnet isabout to go to the outer circumferential side of the rotor. The largerthe contact area between the permanent magnet and the permanent magnetinsertion hole is, the closer to the rotation center the permanentmagnet is located, and the lighter the weight of the permanent magnetis, the stronger the centrifugal force becomes. In the V-arrangement ofthe permanent magnets in which one of the two permanent magnets 6, 7 isshort in length in the radius direction and the other is long in lengthas in the invention, the permanent magnet 7 which is shorter than thepermanent magnet 6 in length in the radius direction is setting up withrespect to the rotation center but light in weight correspondingly tothe short length. The permanent magnet 6 which is longer than thepermanent magnet 7 in length in the radius direction, since it islocated closer to the horizontal with respect to the rotation center onconstruction than that in the isosceles V-shape, is strong incentrifugal force.

Further, as shown in FIG. 2, on the construction, the arcuate spaces 20to 23 for preventing flux leakage are provided for the both end portionsof each of the first and second magnet holes 2, 3 in the bulging shapetoward the outer circumferential side or the inner circumferential side.Further, the first and second magnet holes 2, 3 are providedrespectively with the arcuate spaces 24, 25 for preventing flux leakagewhich bulge toward the outer circumferential side at a curvature largerthan a curvature of the corner portion so as to include the cornerportion of each magnet hole. Therefore, by these arcuate spaces,concentration of stress in the magnet holes in the rotor 10 may bediffused and mitigated.

Further, as shown in FIG. 2, under the constitution of the invention,since the magnet holes 2, 3 for inserting therein the two magnets perpole are provided in the rotor core 11 along the V-shape and the centerbridge 5 is provided between the magnets holes 2,3, the centrifugalforce-resistance increases more by this center bridge. Namely,high-speed rotation is realized.

Further, as shown in FIG. 2, since the eight cavity portions 8 areformed in the rotor core 11, the weight of the rotor 10 which is bynature a weight may be reduced correspondingly, so that mechanical lossin a bearing portion (not shown) which supports a rotor shaft (notshown) fitted into a hollow portion of the rotor 10 may be reduced, andefficiency may be increased. In this case, the cavity portion 8 islocated and formed in the area set by shape and dimension determined bystress limit which generates by the centrifugal force acting on therotor 10 and by shape and dimension determined by judging the locationwhere the influence on a magnetic path is small. Therefore, themechanical strength for the centrifugal force of rotation is notimpaired, the flow of fluxes (magnetic path) by the stator winding (notshown) attached to the slot 14 of the stator 12 and by the permanentmagnets 6, 7 of the rotor 10 is not obstructed, and a bad influence isnot exerted upon characteristics.

Further, since coolant may be taken in the cavity portion 8 of the rotorcore 11 and circulated, the rotor core may be directly cooled, so thatcooling property of the rotor 10 may be improved.

Thus, in the description of the principle in FIG. 3, the d-axis magneticrepulsion-boundary point provided for the rotor is displaced to theshorter permanent magnet side by one slot, while in the second relatedart shown in FIG. 10, the d-axis magnetic repulsion boundary point isnecessarily located in the center of the usual isosceles V-shapedpermanent magnet arrangement. The amount of this displacement isappropriately different according to combination of the slot number ofthe stator of the rotating electric machine and the pole number of therotor.

Further, though the so-called slot stator has been described in theabove description of the embodiment and the figures, since theembodiment of the invention relates to the structure of the rotor, thestator is not limited to the slot stator, a so-called slot-less statormay be used. Also in this case, the similar advantage may be obtained.

Further, the invention may be applied also to a linear motor whichlinearly moves in place of the rotating motor.

According to the electromagnetic steel plate forming member, theelectromagnetic steel plate laminator, the permanent magnet typesynchronous rotating electric machine rotor provided this, and thepermanent magnet type synchronous rotating electric machine of theinvention, in the iron core portion formed between the upper endsurfaces of the two magnet holes arranged in the V-shape in the rotorcore and the outer circumferential portion of the rotor core, thesaturation of the q-axis flux may be suppressed, and both utilization ofthe reluctance torque and improvement of the magnet torque can berealized. In result, since large torque may be obtained also in thestarting time and in abrupt change of load, efficiency can be made good.Therefore, the invention is effective as a drive motor or a generatorfor a hybrid car, a fuel cell car, or an electric car, as a drive motoror a generator for a railway vehicle, and as a generator used in agenerator car for an uninterruptible power supply. Further, theembodiment of the invention is effective also as a drive motor for anindustrial machine such as an elevator, an elevator in a multi-levelparking zone, a compressor or a blower for wind or water power, a fluidmachine such as a pump, or a working machine including mainly asemiconductor manufacturing apparatus or a machine tool.

1. A disc-shaped electromagnetic steel plate for forming a rotor core,comprising: a disc-shaped plate member; first and second magnet holeshaving a first longitudinal side and a second longitudinal side,respectively, and provided in the disc-shaped plate member toaccommodate first and second permanent magnets, respectively, the firstand second magnet holes being provided such that the first longitudinalside and the second longitudinal side extend substantially in parallelwith forward and rear extending directions, respectively, in apredetermined pole pitch angle between rear radial pole pitch line and aforward radial pole pitch line that is positioned at a forward positionwith respect to the rear radial pole pitch line in a rotationaldirection of normal rotation of the rotor core, the first and secondmagnet holes forming a substantially V-shape having a vertex which issubstantially on a center diameter dividing the pole pitch angle tohalf, the first magnet hole being provided at a forward position withrespect to the second magnet hole in the rotational direction, a forwardacute angle between the forward extending direction and the centerdiameter being larger than a rear acute angle between the rear extendingdirection and the center diameter, a forward shortest distance betweenthe first magnet hole and the forward radial pole pitch line beingsmaller than a rear shortest distance between the second magnet hole andthe rear radial pole pitch line; and a center bridge located at thevertex of the V-shape to partition the first and second magnet holes. 2.The disc-shaped electromagnetic steel plate according to claim 1,wherein the first and second magnet holes have an asymmetrical shape. 3.The disc-shaped electromagnetic steel plate according to claim 1,wherein a length of the first longitudinal side of the first magnet holeis different from a length of the second longitudinal side of the secondmagnet hole.
 4. The disc-shaped electromagnetic steel plate according toclaim 1, wherein the first and second magnet holes are positioned sothat a distance of an iron core portion from an outer end surface ofeach hole to a circumferential surface of the disc-shapedelectromagnetic steel plate for forming the rotor core is substantiallysame.
 5. The disc-shaped electromagnetic steel plate according to claim1, wherein arcuate spaces for preventing flux leakage are provided, forboth end portions in a longitudinal direction of each of the first andsecond magnet holes, in a bulging shape toward an outer circumferentialside.
 6. The disc-shaped electromagnetic steel plate according to claim1, wherein arcuate spaces for preventing flux leakage are provided, forboth end portions in a longitudinal direction of each of the first andsecond magnet holes, in a bulging shape toward an inner circumferentialside.
 7. The disc-shaped electromagnetic steel plate according to claim1, wherein each of the first and second magnet holes includes an arcuatespace for preventing flux leakage which bulges outward at a largercurvature than a curvature of a corner portion of the magnet hole so asto include the corner portion.
 8. The disc-shaped electromagnetic steelplate according to claim 1, wherein the first and second magnet holeshave a substantially rectangular shape.
 9. The disc-shapedelectromagnetic steel plate according to claim 1, wherein the first andsecond magnet holes have an arcuate.
 10. The disc-shaped electromagneticsteel plate according to claim 1, wherein a cavity portion is providedon each of the forward radial pole pitch line and the rear radial polepitch line located at both ends of the pole pitch angle of thedisc-shaped electromagnetic steel plate for forming the rotor core, thecavity portion being determined by stress limit by centrifugal force.11. An electromagnetic steel sheet lamination constituted in a blockshape by laminating the plural disc-shaped electromagnetic steel platefor forming the rotor core according to claim
 1. 12. A permanent magnettype synchronous rotating electric machine rotor, comprising: the rotorcore constituted by the electromagnetic steel sheet lamination accordingto claim 11; and a first and a second permanent magnets which areinserted into a first magnet hole and a second magnet hole inside therotor core to generate fields.
 13. The permanent magnet type synchronousrotating electric machine rotor according to claim 12, wherein in aniron core portion formed between the outer end surfaces of the first andthe second magnetic holes and a circumferential surface of the rotorcore, magnetic fluxes formed by the first and the second permanentmagnets are distributed with displacement in the circumferentialdirection from a center of a pole pitch angle provided in the rotorcore.
 14. The permanent magnet type synchronous rotating electricmachine rotor according to claim 12, wherein the rotor is a rotor of an8-pole interior permanent magnet type synchronous rotating electricmachine.
 15. A permanent magnet type synchronous rotating electricmachine comprising: the rotor according to claim 12; and a statorarranged around the rotor.
 16. The permanent magnet type synchronousrotating electric machine according to claim 15, wherein a number P ofmagnetic poles of permanent magnets arranged in magnet holes of therotor and a number M of salient magnetic poles arranged in salient polesof the stator satisfies P=2(n+1) (n is an integer which is one or more)and M=6P.
 17. The permanent magnet type synchronous rotating electricmachine according to claim 15, wherein the rotating electric machine isan interior permanent magnet type synchronous rotating electric machinein which a number of magnetic poles of the permanent magnets is 8 poles.18. A vehicle comprising the permanent magnet type synchronous rotatingelectric machine according to claim 15 used as a drive motor for drivingwheels.
 19. A vehicle comprising the permanent magnet type synchronousrotating electric machine according to claim 15 used as a generator. 20.An elevator comprising the permanent magnet type synchronous rotatingelectric machine according to claim 15 used as a drive motor.
 21. Afluid machine comprising the permanent magnet type synchronous rotatingelectric machine according to claim 15 used as a drive motor.
 22. Aprocessing machine comprising the permanent magnet type synchronousrotating electric machine according to claim 15 used as a drive motor.23. The disc-shaped electromagnetic steel plate according to claim 3,wherein the length of the first longitudinal side of the first magnethole is longer than the length of the second longitudinal side of thesecond magnet hole.